A unique stepped multifunctionality of perfluorinated aryl compound and its versatile use in synthesizing grafted polymers with controlled structures and topologies

A unique stepped multifunctionality of perfluorinated aryl compound for the first time was studied by using model reactions between 2,5‐dipentafluorophenyl‐1,3,4‐oxadiazole (FPOx) and mono functional p‐cresol at different reaction conditions. Four distinctively different levels of reactivity were discovered for the para and ortho C? F of FPOx, which could be easily triggered by the reaction temperature in the range of r.t. to 160 °C. C? F of all levels of reactivity could react quantitatively with nucleophiles (such as phenoxide); and by controlling the reaction conditions, the low‐level‐reactivity C? F would not interfere with the reaction of C? F of higher reactivity. Application of this multistepped reactivity of FPOx in quantitative postpolymerization functionalization of polymer was successfully demonstrated. Stoichiometric amount of p‐cresol, with the molar feed ratio of p‐cresol in relative to the repeat unit of the polymer of FPOx and 6F‐BPA in the range of 1–4, could be readily grafted onto the polymer by simply controlling the reaction temperature. FPOx‐based, versatile one‐pot synthesis of high molecular‐weight grafted polymers with well‐controlled structures and topologies were also demonstrated. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011     

基于并五苯/酞菁铅异质结的近红外光敏有机场效应管(英文)

采用并五苯(Pentacene)和酞菁铅(PbPc)两种有机材料作为有源层,制备了异质结有机光敏场效应管。在波长为808 nm、强度为124 mW/cm2的近红外光照条件下,异质结phOFET获得最大的光暗电流比达4.4×104,栅压为-50 V时的最大光响应度为118 mA/W,比单层酞菁铅phOFET分别高出766倍和785倍。在经过120 h后,器件的最大光暗电流比和最大光响应度分别稳定于5.4×104和326 mA/W附近。由于在异质结phOFET中采用了对近红外光具有高吸收效率的酞菁铅作为光敏层,而高空穴迁移率的并五苯材料作为靠近栅介质的沟道层,光生载流子的产生与传输能力得到了有效的提高。实验结果表明,基于并五苯/酞菁铅的有机异质结应用于光敏有机场效应管的结构设计中,可以使phOFET成为一种同时具有良好光敏性及稳定性的近红外光探测器件。     

Fabrication of 6,13‐bis(triisopropyl‐silylethynyl)–pentacene thin‐film transistors with the silver ink transfer method using a polymer stamp

We fabricated 6,13‐bis(triisopropylsilylethynyl)–pentacene (TIPS–pentacene) thin film transistors using a direct metal transfer method. Using different metals, such as Au and Ag ink, electrode patterns are formed from the relief region of the polymer mold. TIPS–pentacene TFTs using the Ag ink transfer method show a similar performance to those using the Au metal transfer method. This method has advantages over the Au metal transfer method because it does not require vacuum equipment and a dry etching process. The self‐assembled monolayer (SAM) treated device exhibits a carrier mobility of 9.5 × 10^–2 cm²/V · s, and an on/off ratio of 4.6 × 10⁴. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Excited‐State Dynamics of Pentacene Derivatives with Stable Radical Substituents

The excited‐state dynamics of pentacene derivatives with stable radical substituents were evaluated in detail through transient absorption measurements. The derivatives showed ultrafast formation of triplet excited state(s) in the pentacene moiety from a photoexcited singlet state through the contributions of enhanced intersystem crossing and singlet fission. Detailed kinetic analyses for the transient absorption data were conducted to quantify the excited‐state characteristics of the derivatives.     

Lowest Singlet Exciton in Pentacene: Modern Calculations versus Classic Experiments

Based on simple model calculations, the expected magnitude of the field‐induced shift observable in electroabsorption is estimated for three alternative assignments proposed in the literature for the lowest singlet excitation of the pentacene crystal (pure Frenkel exciton, pure charge‐transfer exciton, or a mixture of both). The results are compared with the corresponding experimental value, which is also known from the literature. The latter turns out to be compatible only with the mixed parentage of the pertinent state, which contains the charge‐transfer contribution in the range from 25 to 70 %. The conclusion is discussed in the context of the present controversies concerning the existing experimental and theoretical evidence on this subject.     

近岸及河口海水中全氟化合物的固相萃取富集/超高效液相色谱-串联质谱测定

建立了近岸及河口海水中全氟辛基磺酸(PFOS)、全氟辛酸(PFOA)、全氟十一酸(PFUn A)、全氟十二酸(PFDo A)、全氟十三酸(PFTr DA)、全氟十四酸(PFTA)6种全氟化合物(PFCs)的超高效液相色谱-串联质谱(UHPLC-MS/MS)测定方法。使用C18固相萃取小柱对500 m L水样中的目标物进行富集后,用15 m L甲醇-乙酸乙酯混合淋洗液(4∶1)进行洗脱,浓缩,定容至1.0 m L后,用Kinetex XB-C18色谱柱以均含5.0mmol/L甲酸铵的甲醇-水为流动相梯度洗脱方式进行分离,电喷雾负离子模式(ESI-)电离,多重反应监测模式(MRM)以及内标法对6种PFCs进行定性定量测定。优化了固相萃取、色谱分离及质谱测定条件,考察了海水盐度对方法回收率的影响。在优化实验条件下,方法在2.0,5.0,10.0 ng/L加标水平下,实际海水样品的回收率为80.1%~117.4%,在2.0 ng/L加标水平的相对标准偏差(RSD,n=7)为8.2%~12.1%。6种PFCs的线性范围为0.5~50.0μg/L,相关系数大于0.999 0;方法的定量下限(LOQ,S/N=10)为0.5~1.5 ng/L。该方法具有样品前处理简单、分析速度快、选择性好的特点,适用于近岸及河口海水中全氟化合物的快速测定。     

HPLC-MS/MS与ICP-MS分别测定血液中14种全氟化合物及常见金属元素

为了解广东儿童血液中全氟化合物(PFCs)和常见金属元素的含量水平,为儿童健康评估提供数据,该文采用蛋白沉淀法提取样品,高效液相色谱-串联质谱(HPLC-MS/MS)检测样品中14种PFCs。同时,以石墨全自动消解仪消解血液样品,电感耦合等离子体质谱(ICP-MS)检测血液中钙(Ca)、镁(Mg)、铁(Fe)、锌(Zn)、铜(Cu)和锰(Mn)元素。结果显示,儿童血液中14种PFCs被普遍检出,其中全氟辛基磺酸(PFOS)和全氟辛基羧酸(PFOA)的检出率及浓度最高,但在一些个体中发现较高浓度的其它碳链PFCs。PFCs浓度有随着年龄增长而下降的趋势,但除了全氟丁基磺酸外,无性别差异。另一方面,儿童血液中检出的Ca、Mg、Fe、Zn、Cu和Mn含量在正常范围内,未发现有性别差异。研究显示PFCs普遍存在儿童血液中,儿童PFCs暴露水平的研究应引起重视。在今后的监测中,不仅要关注PFOS和PFOA,也要关注其它碳链PFCs。     

Nickel(II) Bisporphyrin-Fused Pentacenes Exhibiting Abnormal High Stability

A series of largely π-extended multichromophoric molecules including cross-conjugated, half cross-conjugated, conjugation-interrupted and linearly conjugated systems were synthesized and characterized. These multichromophoric molecular systems revealed interesting structural-property relationships. Bisporphyrin-fused pentacenes Pen-1 b and Pen-2 a showed rich redox chemistry with 7 and 8 observable redox states, respectively. The linearly-conjugated bisporphyrin-fused pentacenes ( Pen-1 b and Pen-2 a ) possess much narrower HOMO–LUMO gaps (1.65 and 1.42 eV redox, respectively) and higher HOMO energy levels than those of their pentacene analogues (2.23 and 2.01 eV redox, respectively), similar to those of much less stable hexacenes and heptacenes. An estimated half-life of >945 h was obtained for bisporphyrin-fused pentacene Pen-2 a , which is much longer than that of its pentacene analogue ( BPE-P , half-life, 33 h).     

Effect of humidity and temperature on nano/microtribolgical properties of perfluorinated carboxylic acid and hydrogenated carboxylic acid self‐assembled monolayers deposited on aluminum‐coated silicon substrate

Two series of perfluorinated carboxylic acid (FC) and hydrogenated carboxylic acid (HC) self‐assembled monolayer (SAM) films were prepared on aluminum surfaces separately by chemical vapor deposition. The formation, structure and morphology of these films were characterized by measuring contact angle with ellipsometric method, x‐ray photoelectron spectrometry, and atomic force microscopy, respectively. FC and HC SAMs with long chains formed more densely packed films than those with short chains did. The comparative micro/nanoscale friction and adhesive properties of FC and HC SAMs, with various chain lengths on aluminum‐coated silicon substrate, were investigated. The influence of environmental conditions, such as relative humidity (RH) and temperature, on the friction and adhesion behavior was studied. Micro/nanotribological properties of the films were greatly influenced by their backbones and terminal groups. FC SAMs with long chain exhibited adhesion‐resistance, friction reduction, and environmental independence. Copyright © 2009 John Wiley & Sons, Ltd.